Precision Twist Drill 5996521 Cobalt Drill Bit 0.339 in

Product Description

The PRECISION TWIST DRILL 5996521 is a cobalt screw machine length drill bit sized at 0.339 inches (Letter R) with a 135-degree split point. Built to M42 cobalt steel spec, it delivers high-performance drilling in hard and abrasive materials where standard HSS bits lose their edge quickly. The split point geometry reduces walking and lowers thrust force at entry. Web thinning improves chip evacuation and reduces heat buildup at the cutting tip. This bit is sold individually and is suited for production and maintenance drilling in metal fabrication, machining, and mechanical trade work.

This drill bit is designed for use in hard workpiece materials including alloy steels, stainless, and similarly tough stock. The screw machine length format — shorter overall than jobber length — increases rigidity and reduces deflection, making it a practical choice for drill press, turret lathe, and CNC applications where stub-length control is needed. The straight cylindrical shank fits standard drill chucks without adapters. Right-hand spiral flute geometry is compatible with conventional right-hand rotation spindles found on nearly all machine tool setups.

Key Features

• M42 cobalt construction rated for drilling hard and abrasive materials
• 135-degree split point reduces thrust and eliminates center-punch requirement on most metals
• Web-thinned, tapered web configuration improves chip flow and reduces heat at the tip
• Screw machine (stub) length increases rigidity and minimizes deflection versus jobber bits
• Regular spiral flute at 2.5xD ratio balances chip clearance and cutting edge support
• Straight cylindrical shank fits standard three-jaw drill chucks without reduction sleeves
• ANSI specification compliance for dimensional consistency

Compatibility

Designed as an OEM-style replacement or direct-use drill bit for applications requiring screw machine length cobalt bits in the 0.3000 to 0.3500 inch diameter range per ANSI standards.

Installation Notes

Installation of this drill bit is performed by machinists, tool-and-die trades, and mechanical maintenance technicians. Secure the straight shank fully in a properly rated drill chuck before operation and verify spindle speed is appropriate for the workpiece material and bit diameter. Use cutting fluid or coolant where possible to extend tool life, noting this bit does not have coolant-through capability. Inspect the cutting edges before each use and replace the bit if chipping or wear is observed at the split point.